According to Israeli company Trusteer, which specialises in tracking the activities of Zeus and its variants, there are now at least 26 different configurations to attack one company alone, Money Bookers.

Each configuration represents a separate set of slightly instructions on how to attack the sites associated with a brand, with the number detected being in this example similar in scale to the number of configurations that would be created to attack much larger companies.

One thing that becomes clear is that along with the other services attacked – Web Money and Nochex, netSpend – this Zeus campaign is going after second-tier companies. Perhaps fearing attention, the criminals appear to be steering clear of large consumer payment services such as PayPal.

“As far as we know PayPal has very strong fraud detection and prevention capabilities similar to any large bank. While this is not an insurance against attacks, fraudsters are probably less likely to get money out of such websites,” commented Trusteer’s Amit Klein.

Ironically, the criminals have also gone after a service called e-gold, which several years ago was itself accused of being a conduit for money laundering. Configurations used against the site are sophisticated enough to try and trick the login screen into sending out an alternate password to access targeted accounts.

“We believe this trend of targeting online payment providers will continue as more retailers allow these alternate payment methods with their websites,” said Trusteer.

What Trusteer hasn't been able to document is whether the attacks it has detected have been successful. If the pattern of attacks through 2009 and 2010 on consumers is any guide, knowledge of that dimension tends to come later as victims emerge.